1. Field of the Invention
Embodiments of the invention relate to an image display device capable of selectively implementing a two-dimensional plane image (hereinafter referred to as ‘2D image’) and a three-dimensional stereoscopic image (hereinafter referred to as ‘3D image’).
2. Discussion of the Related Art
Recently, an image display device may selectively implement a 2D image and a 3D image due to the development of various contents and circuit technology. The image display device implements the 3D image using a stereoscopic technique or an autostereoscopic technique.
The stereoscopic technique, which uses a parallax image between left and right eyes of a user with a high stereoscopic effect, includes a glasses type method and a non-glasses type method, both of which have been put to practical use. In the non-glasses type method, an optical plate such as a parallax barrier for separating an optical axis of the parallax image between the left and right eyes is generally installed in front of or behind a display screen. In the glasses type method, left and right eye images each having a different polarization direction are displayed on a display panel, and a stereoscopic image is implemented using polarized glasses or liquid crystal (LC) shutter glasses.
An LC shutter glasses type image display alternately displays a left eye image and a right eye image on a display element every one frame and opens and closes a left eyeglass and a right eyeglass of LC shutter glasses in synchronization with a display timing, thereby implementing the 3D image. The LC shutter glasses open only the left eyeglass during odd-numbered frame periods, in which the left eye image is displayed, and open only the right eyeglass during even-numbered frame periods, in which the right eye image is displayed, thereby making binocular disparity in a time division method. In the LC shutter glasses type image display, because the LC shutter glasses are turned on in a short period of time, a luminance of the 3D image is low. Further, a 3D crosstalk is extremely generated because of the synchronization between the display element and the LC shutter glasses and the ON/OFF conversion response characteristic.
As shown in FIG. 1, a polarized glasses type image display includes a patterned retarder 2 attached to a display panel 1. The polarized glasses type image display alternately displays left eye image data L and right eye image data R on the display panel 1 every one horizontal line and converts polarization characteristics of light incident on polarized glasses 3 using the patterned retarder 2. Through such an operation of the polarized glasses type image display, a left eye image and a right eye image may be spatially divided, thereby implementing a 3D image.
In the polarized glasses type image display, because the left eye image and the right eye image are adjacently displayed on the adjacent horizontal lines of the display panel 1, a range of a vertical viewing angle, in which a crosstalk is not generated, is very narrow. The crosstalk is generated when a doubled image of the left eye image and the right eye image is displayed at a location of the vertical viewing angle. To prevent the crosstalk in the polarized glasses type image display, as shown in FIG. 2, a method for forming black stripes BS in an area of a patterned retarder 2 to thereby widen a vertical viewing angle of the 3D image had been proposed in Japanese Laid Open Publication No. 2002-185983. However, the black stripes BS of the patterned retarder 2 used to widen the vertical viewing angle cause side effects resulting in a large reduction in a luminance of a 2D image.